The technology of providing copolymers and cosmetic compositions satisfying several demands of modern rheology modifiers or cosmetic polymers is already highly advanced.
WO 01/62809 A1 describes a cosmetic means comprising at least one water-soluble or water-dispersible polymer which comprises in incorporated form
a) 5 to 50% by weight of at least one α,β-ethylenically unsaturated monomer of formula I

in which R1 is hydrogen or C1-C8-alkyl, and X1 is O or NR2, where R2 is hydrogen, C1-C8-alkyl or C5-C8-cycloalkyl,
b) 25 to 90% by weight of at least one N-vinylamide and/or N-vinyllactam,
c) 0.5 to 30% by weight of at least one compound having a free-radically polymerizable, α,β-ethylenically unsaturated double bond and at least one cationogenic and/or cationic group per molecule,
d) 0 to 30% by weight of at least one α,β-ethylenically unsaturated monomer of formula II

in which R3 is hydrogen or C1-C8-alkyl, X2 is O or NR5, where R5 is hydrogen, C1-C8-alkyl or C5-C8-cycloalkyl, and R4 is hydrogen or a linear C1-C22-alkyl radical
or the salts thereof.
One polymer of this disclosure comprises 30% by weight of tert.-butylacrylate, 19% by weight of n-butylacrylate, 27% by weight of N-vinylpyrrolidone, 17% by weight of N-(3-(dimethylamino)propyl)acrylamide in an about 90% protonated form, 5% by weight of methacrylic acid and 2% by weight of an ethoxylatet polysiloxane (Belsil® DMC 6031, Wacker).
However said polymer is still to be optimized with respect to its performance and price characteristics. First of all, using an additional ethoxylated polysiloxane makes production costs higher. Furthermore said monomer confers a certain softness to the polymer which would lead to somewhat less stable since higher flexible polymer films. This same effect is known to be generated from acrylic esters like n-butylacrylate, since this monomer likewise has a soft character. However, weak and highly flexible polymer films on ceratinic surfaces or the skin would render a hair style or a cream layer more unstable during time, especially in windy or rainy weather and at the worst would completely disintegrate the hair style formed or the cream layer applied. This effect can be partially attenuated by means of applying a larger amount of polymer respectively cosmetic means or by repeatedly applying it, thus resulting in higher costs per application or per effect desired.
Completely omitting n-butylacrylate or both n-butylacrylate and the ethoxylated polysiloxane from the water-soluble or water-dispersible polymer of the cosmetic means as indicated for certain of the WO 01/62809 A1 embodiments comprising the combination of a), b) c) and d) supra would not improve the situation either, since then a rigid polymer film will form on the hair or skin. Said rigid film is able to properly maintain the shape of a hairstyle, if said hair style remains mechanically unaffected or almost unaffected. However, repeated hair combing, brushing, moving through it with the hands or even windy weather will bent the somewhat rigid polymer film and partially lead it to break. A consequence thereof is that conditioning and styling performance will drop and polymer flakes will trickle out of the hair do or from other ceratinic surfaces or the skin, a perturbing and unpleasant situation especially for dark-haired people. This effect can unfortunately not be neglected since such polymer in solution per se is already turbid not transparent, whereas transparency would reduce perception of polymer-born flakes. A further drawback of such even reduced polymer flaking is that one inescapably would require more of polymer per application or more applications per time in order to come to a sufficient and long lasting conditioning, styling or setting effect. This again would make the cosmetic means more expensive.
These are only some of the drawbacks of the prior art which are to overcome.